In semiconductor technologies, backside illuminated (BSI) sensors are used for sensing a volume of exposed light projected towards the backside surface of a substrate or sensor layer. The backside illuminated sensors can be formed in the substrate and light projected towards the backside of the substrate can reach the sensors. However, during BSI sensor processing, stress on the substrate or sensor layer is known to impact leakage current or dark current. In particular, stress on the device substrate or sensor layer may be caused by subsequent color filter processing and/or device packaging after leaving a fabrication facility, which can cause variations in dark current and thus negatively impact device performance or even possibly cause device degradation.
Therefore, while existing methods of fabricating semiconductor devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect. In particular, improvements in backside illuminated sensor processing and/or the corresponding sensor substrate are desired.